Note: Descriptions are shown in the official language in which they were submitted.
~Z6~?8
The present invention relates to improvements in
electrophotographic devices, and more particularly to
improvements in electrophotographic devices which ca~ obtain
images of good quality by substantially uniformalizing a
potential at the surface of a photosensitive body at the
termination of copying, by adjusting optical systems, by
uniformalizing exposures, and the like.
There are two typical types of electrophotography.
One type uses photosensitive paper and the other type uses
10 conventional paper on which is transferred an image which has
been formed on a photosensitive layer consisting mainly of CdS,
zinc oxide and the like.
The invention relates to the latter type. A photo-
sensitive member having a photoconductive layer consisting of
CdS, zinc oxide, Se, etc. and a conductive base of Al, etc. is
disposed around the periphery of a rotatable drum. This drum-
type photosensitive member, similar to a belt-type photo-
sensitive member, is disposed at the center portion of the
electrophotographic device and around this photosensitive
20 member are disposed a positive or a negative corona charger for
applying charges uniformly on the photoconductive layer (either
a positive charge or a negative charge as determined, for
example, according to whether the photoconductive layer is of
the P type or of the N type), an optical system, a corona
discharger (positive or negative) for separating a transfer
paper from the drum or a corona charger for improving the
transfer of the image.
In a dev:ice such as that mentioned above, when all
the processes necessaxy for copying are repeated in order to
30 obtain a number of copies, the rotation of the dr~n is stopped
simultaneously with the cutting off~of the power source for the 2
chargers, a uniform influence is not effected by the corona
charger with the provision of said chargers in spaced relation
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~IZ6798
to the periphery of the drum. As a result, there is produced
a part which is charged and a part which is not charged so that
if this condition is left as it is, the photoconductive layer
is differently affected. Therefore, at the time of successive
copying, a charge is not imparted uniformly to the photo-
conductive layer, which often produces unevenness of the image
which results in being unable to obtain an image of the best
quality.
The invention eliminates the aforementioned disadvantages.
An uneven or a dim image sometimes is caused by a slight error in
the length of the light path of an optical system from an
original to be exposed to a photosensitive body between a device
in the design stage and an actual device. Furthermore, it is
difficult to illuminate uniformly the original, so that
sometimes there is produced a difference of exposure between the
central part and the peripheral part of a light image.
The purpose of the present invention is to eliminate
the disadvantages noted above.
An object of the invention is to substantially uni-
formalize the surface potential of a photosensitive body at thetermination of the copying process in order to eliminate
unevenness or fog from the image. This is because the surface
potential of the photosensitive body at the termination of the
copying process partly lacks uniformity~due to various charging
means and often is charged positively in some parts and
negatively in other parts. If the successive copying operations
are continued in the condition described, the copying process
progresses with the surface potential of the photosensitive body
remaining uneven to thus produce a charge unevenness and a
resulting image ~mevenness. Such unevenness is improved by the
provision of a substantially uniform potential of the photo- j
sensitive body at the termination of the copying process.
However, it is not always necessary to completely uniformalize
~L~L26798
the surface potential, but in order to obtain tolerable results
it is preferable to approximately uniformalize the potential in
the vicinity of zero potential. Furthermore, unevenness and
fog in the image are sometimes caused by the optical system.
Adjustment of magnification of the original and of its image,
and adjustment of the focus are often out of alignment in
manufacture. Another object of the invention is to simply adjust
the foregoing and to uniformalize the exposure at the time of
slit exposure in the central portion as well as in the peripheral
portion.
The present invention provides a repeatedly copying type
electrophotographic device comprising a photosensitive member
having a photoconductive layer, a charging means and an exposing
means for forming an electrostatic latent image on said photo-
sensitive member, developing means for visualizing said
electrostatic latent image, means for transferring the visible
image to a copying material, means for fixing said visible image,
means for transporting copying materials, and paper rejection
tray means, characterized in that means is provided for
substantially uniformalizing a potential of the photoconductive
layer before the whole device stops after the termination of the
copying process.
The invention also provides a repeatedly reproducing type
electrophotographic device comprising a photosensitive member
having a photoconductive layer, a charging means and an exposing
means for forming an electrostatic latent image on said photo-
sensitive member, means for transporting recording materials,
and means for forming a developed image on the recording material,
characterized in that means is provided for substantially
uniformalizing a potential of the photoconductive layer beore
the whole device stops after the termination of image forming
operations.
BRIEF DESCRIPTION OF THE DRAWINGS
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Figure 1 is a perspective view of the exterior
of a copying machine embodying the invention;
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iL3~;Z6798
Figure 2 is a front longitudinal sectional view of the
machine of Figure l;
Figure 3 is a circuit diagram of a power source system;
Figure 4 is a timer circuit diagram;
Figure 5 (sheet 1 of the drawings) is a diagram of an
electric circuit for driv.ing and controlling an original base;
Figure 6 is a diagram of an electric circuit for
driving and controlling a sheet original;
Figure 7 is a diagram of a jam detection circuit I and
a circuit which detects the presence of paper within a cassette;
Figure 8 is a diagram of a jam detection circuit II;
Figure 9 is a timing circuit diagram for feed paper ~ams;
Figure 10 is a temperature control circuit dia~ram;
Figure 11 shows an arrangement of a microswitch on the
sensitive drum;
Figure 12 is a time chart,
FigureS13 (sheet 9 of the drawings~ ~ 14 are
longitudinal sectional views of an optical system ~hich embodies
one form of the present invention;
Figure 15 is a view explaining the principle of the
same;
Figure 16 (sheet 13 of the drawings~ is an enlarged view
of the exposure part of the above;
Figure 17 is a plan view of a slit plate of the above;
Figure 18 is a plan view of the control plate;
Figure lg is a sectional view showing one form of paper
ejection tray constructed according to the invention; and
Figure 20 is a sectional view of another form of paper
ejection tray constructed according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the invention will now be described.
In this embodiment, a photosensitive body compxises a
three-layer construction, namely a surface insulating layer, a
conductive base material, and a photoconductive layer inserted
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~26798
between the surface insulating layer and the conductive base
material. The process of operation consists first in applying
a D.C. corona discharge to the photosensitive body by a primary
charge means so as to apply a positive charge. Then an AC corona
discharge is applied to the photosensitive body and at the same
time a light image of the original to be copied is exposed. The
photosensitive body is totally exposed to thereby increase the
contrast of an electrostatic latent image and a visible image is
formed by toner development having a polarity opposite to that of
the electrostatic latent image. Although the foregoing process
will be described in greater detail, it is not our intention to
limit the invention to the foregoing process.
Initially, a mechanical operation is described
schematically, and the operation of the electrical system follows.
The copying machine is based on the liquid development
transfer system and is able to easily copy sheet originals such
as papers, and also thick originals such as books.
Referring now to ~igure 1, there is provided a machine
case 101, a sheet original feed part 102, and an original base 2
on which a thick original (hereinafter called "a book original")
is positio~d, an original holder cover 21 being placed on the
base. There are shown guide rails 1031, 132 for the original
base, a cassette 20 for housing a transfer paper 21, a tray 32 on
which are placed transfer papers ejected outside the machine, a
main switch 104, a group of alarm lamps 1051, 1052, 1053, and
1054, a knob 106 for selecting the number of papers to be
continuously copied from the book original, a copy button 107
which serves also for a re-start (as hereinafter described), a
stop button 108 fcr releasing the continuous copying of the book
original, and a dial lOg for controlling copying concentration
interlocked with the diaphragm of the lens.
The operation of the copying machine ~ill be
: ~Z679~
~_scribed, referring to Figure 2 first in connection ~ith
sheet originals. ~fter ~he lapse of the start preparation
time, when a sheet original is inserted from the sheet
original guide 37 into the sheet original feed first roller5
31 and 32 at the sheet original feed part 102 which rotates
in synchronism with ~ constantly rotating drum 1, the original
:. is-transporte~ leftwards in Figure 2. When the extreme end of
the original is detected by a sheet. original timing lamp 5 and
a light receiving element 38, the sheet original feed first
.. . . .
rollers stop and the original also stops. Then, wh~n the drum
reaches.the position as required and an original start signal
- is transmitted, the sheet original feed first rollers 31 and
32 begin to rotate again and the original is. transported
leftwards in synchroniz.ation with the drum 1 and is ejected
outside the machine by sheet original feed second rollers 41
and 42 During that time, the original passes above an .
original glass 40 and i5. exposed to light radiation from the
hottom.by two illumina~ing-lamps.6. An image of said original
. is formed on the ~rum 1 at the exposure part 41 by ~he
20 reflec~ion mirror 7 and the in-mirror lens 8. .
. The d.rum 1, which has a photosensitive layer ~overed
with a transparent insulation layer, always ro.tates.in a
clockwise direc~ion as shown in Figure 2. The drum 1 is first
chargea positively by a positive charger 9 which is supplied.
. with a positive high current fr~m a high voltage source 3
When the drum then xeaches an exposure par~ 41, an image from
the illumination part 39 is slit exposed and simultaneously an
AC charge is supplied thereto by an AC char~er 10 which is
supplied with an AC high voltage current from ~he high voltage-
source 34. By a general exposure through the general exposurelamp 12 successively taking place, an electrostatic latent
image is formed on the surface of the drum and enters a
developing machine ~2.
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2~791~
The developing machine 42 coMprises a tank 1~ for
a developing solution 43, a pump ~4 for stirring and pumping
the developlng solu~ion, and a developing electrode 13, said
electrode 13 always being pressed against the drum 1 by means
of a spring 45 which maintains a fine clearance therebet~een.
The electrostatic latent image formed on the drum l is
developed and is image-formed by toner in the developing
solu~ion 43 pumped on ~he developing electrode 13. Then, a
charge by a nega`tive high current from the high volta~e source
34 at a minus charger 15 presses out excessive developing
solution in the drum 1 without disturbing the lmage. Then, the
transfer paper ~1 transported from the paper feed part is
adhered closely to the drum 1 and the image on the drum 1 is
trans~erred to the transfer paper 21 by the char~e by a
positïve high current from the hish voltage source 34 at the
transfer charger 16.
The transfer paper 21 already transferred with its
image is separated from the drum 1 by means of a separation
belt ~5 and is introduced into a drying-and-fixing part 46. Thç
remaining toner and developing solution are wiped away from the
drum 1 by edges 171 and 181 of a skirt 17 and of a blade 18,
respectively, and the drum repeats for its successive cycle.
The aeveloping solution wiped ~way by means of the skirt 17 and
the blade 18 is introduced into the developing machine 42
through a peripheral groove 11 made in both ends of the drum 1
and it serves for another development. A toner receiving
member 19 is provided which is adhered closely to the drum 1
to prevent the toner solidified at the rear of the blade 18
from sticking to the drum and dropping off.
On the other hand, the transfer paper 21 is housed
in the cassette 20 and is detachably provided in the paper f~ed
part located at the lower part on the left hand side of the
machine. Various kinds of cassettes are available according to
.
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- he sizes of the several kinds of transfer paper and they may
be replaced easily whenever necessary. The transfer paper 21
is put on the middle plate 47 within the cassette 20 and the .
transfer paper 21 is always pushecl up on the uppermos-t portion
of the cassette 20 by pushing up t:he middle plate 47 by the
action of a sprin~ 4B. In this case, the spring constant o~
the spring 48 is suitably selectecl so as to maintain the force
by which the uppermost transfer paper is pushed up at a ''
constant magnitude irrespec~ive of the number of transfer
papers 21 within the'casse~te 20.
- . ' When the drum l reaches a predetermined position, a
- signal.is produced to move down the usually rotating paper feed .
'roller ~2 which in turn is placed in contact with the transfer
paper at the uppermost portion in the cassette 20, and pressing' -
down a given.amount of the trans~er paper. With this, a . .'
separation pawl 49 mounted on both sides of the extreme end of '
the cassette 20 and rested on the uppermost transfer paper moves
down with it's own weight. A piece of transfer paper 21 is
separated by the rotation of the paper feed roller 22 and ~y the
action of the separation pawl 49 and-is transported in'the right
' airection as shown in Figure 2. However, timing rollers 23l and
232 located nearby will stop immediately after the papèr feed
roller 22 has been moved down so that the transfer paper 21
sent out of the cassette 20 slackens between paper guides-35
. . " ' , , 1
and 352 in such a state that the extreme end of the paper hits '
against the connection of tXe ~iming rollers 23l and 232. .'
Immediately after that, the drum l transmits a signal to start'.
feeding'paper, and the timing rollers 23.l and 232 begin to
' rotate to feed the transfer paper 21 at a speed'commensurate
with the surface speed of the drum l. On the other hand, after.
the lapse of a given time, the paper feed roller 22 which has
~oved down moves upwardly ~gain separating from .the trans~er
paper 21, and thereafter paper feeding is carried out by a
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~Z6791~
~ per feed means provided after the timing rollers 231 and
232 '
As previously mentioned, the already transferred
transf~r paper 21 adhered closely to the drum 1 is separated
from the drum 1 by means of the separation belt 25. The
.separation belt 25 is a narrow endless belt and it is connected
to the separa~ion roller 24, turning pulleys S0, 51 and
-pulleys 521, 522, 523, and 524, arranged in a slightly spaced
relation with the drum 1. The belt between the pulley 52
10 and the separation roller 24 is rested on the drum l in a :
position corresponding to the end of the side o~ the transfer
. .
paper, and the belt between the pulleys 522 and 523 passes
the position got out of the course where the transfer paper
- passes by the action of turning the pulleys S0 and 51.-The
separation bèlt 25 is driven by the separation roller 24 at
the same speea as tha~ of t~e drum 1. At the time when the
:trans~er paper ~1 is adhered c~ose~y to the drum 1 in the
transfer procèss, the end of one side of.the drum pinches the
separation belt 25 therebetween. As a result, when the
. 20 separation belt 25 is separated from ~he drum 1 by means of .
the separation roller ~4, the one side of the ~ransfer paper
21 adherea.closely to the drum is forcibly separate~-from the .~:
drum. The transfer paper ~1 having.its one end come off is
. completely separated from the drum 1 by the firmness of the .-
transfer paper, by ~he.force of the air blown out oE a blower
53 and blowing out: fr.om a blow outlet 271 through a blow-out
duct 27, and ~ a negative pressure proaucea by a suction .
blower 26, and is sent into the drying-and-fixing part 46.
In ~he drying-and-fixing part 46, the transfer paper.
21 moves forwardly having its back adhered closely to the hot
plate 28 which encases a hea$er therein and is dried and fixed
by conduction heat from the hot plate The transfer paper 21
dried and fixed passes through first ejection rollers 291 and
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2~ and a~ter the char~e that remains on the surface of the
paper has been removed by a discharger 31l the transfer paper
is introduced to an outlet 54 by second ejection rollers 30
and 32 and is ejected onto the tray 32.
The operation in the case of a book ori~inal will
now be described. The "sheet original" condition is changed
into the "book original" condition by turning the change-over
knob liO at the ex~reme end of the ori~inal base and then
- suitably moving the original base leftwards as shown in Figure
2. In this way, by moving the original base 2 from the "sheet
original" position to the "book original" position, the supply
of a drive current to the sheet original feed part 102 is
disconnected so that all the circuits may be changed-over for
- use with h . book original.
Thè book original to be copied is put on the original
base glass 55 adjusting the extreme end of the original to the
extreme end 55 of the glass and is held by the holder cover 2 ,
.
- and when a copy button 107 is depressed, the original base 2 is
moved leftwards as shown in Figure ~ by an original start
signal in synchronization with the per~ipheral speed of the
drum 1, in a manner similar to that of the sheet original~ for
slit exposure. In the midst of travel, the original base 2
produces a paper feed start signal for prosecution o paper
feea in synchronization with the exposure. At the termina~ion
of exposure, the original base 2 stops its leftward movement,
~etecting its position, and immediately returns in a reverse
direction, that is, rightwardly. This return speed is faster
-than the reciprocating speed so that the efficiency of copying
may be promoted. When the original base is returned to the
initial position for the book ori~inal, the original base 2 is
cut to be driven and stops.
~ lso, when a great numbPr of copies of a book ori~inal
are required, this can be easily carried out by means of a
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~ L~2~798 - .
ounter 106 interlocked wi~h the copy button 107. The counter
106 counts by detect;ng movement of the original base and
keeps the copy button 107 in a condition such that said button
~eing depressed till the termination of counting the number of
papers set, thus enabling to copy a great nu~ber of copies.
The operation other than the above-described is the
same as the case in the shee~ original.
In this copying machine, the drum 1 is so designed
- that standard size sheets up to A3 in width may be copiea, and
the length o~ the outer periphery of the arum is sLightly longer
than the length of an A3 sheet. Therefore, in the case of an
A3 sheet original, one sheet can be copie~ per single rotation
of the drum 1, and if an A4 original is fed in a lengthwise
direction and in a direction at right angles, two sheets can be
copied per single rotation of the drum 1. On the other hand,
in the case ~f a book original, it requires almost the same
time of backward movement as of forward moyement followed by
the forward movement texPosure process) of the original base 2
so $hat the time requirea for copying one piece takes
approxLmately twice that for ~he sheet original. In other
words, in the case of an A3 original, one can be copied pe~ two
rotations of the drum, and an A4 original can be copied pPr
single rotation of drum.
The difference o~ cycle due to the size o~ paper, as
described above, is discriminated by a signal from the casse~te
20 while the difference of cycle due to the kind of original
(book or sheet) i~s discriminatea b~ a signal obtained by
changing the position of the original base.
A start preparation to be made prior to a copying
operation, a suspension condition after the termination of the
copying operation, and a re-start will now be described. ~s
dcscribed above, this copying machine has a liguid development
system in which toner in the developing solution is fixed by
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the v~porization of the carrier liq~lid. ~lso, since the toner
or the develc~ping solution remaining on the drum 1 after
transEer are cleaned by the skirt 17 and by the blade 18, a
fine amount of toner is always accumulated in the vicinity o~
the edges 171 and 181 of the skirt and of the blade. If the
machine is stopped and left as it is the condition mentioned
above, the carrier in the edges 171 and 181 vaporizes and the
toner solidifies. If the cdrum 1 is ro~ated again in that
condition, the edges 171 and 1~1 and the surfaces of the drum
1 are damaged, or the quality of an image is affectea~ In this
copying machine, therefore, even if the main switch 104 is
tu.rned on, the drum 1 is not rotated but only the pump 44 for
.
the developing machine 42 is in operation, and at the same time
when the developing solution is stirred the developing solution
43 is forced up to reach the liquid feed pipe 56, thus pouring
into the cleaner 18. A~ter the lapse of a given time, the toner
in the edges 171 and 18~ softens and then the drum 1 begins to
rotate to wipe o~f the softened toner, and a~ter the drum has
. been rotated at least by a half turn, the sheet original feed
2a rollers 3i ancl 32 in the sheet original feed part 102 begin to
rotate to provide the commencement of a copying operation.
. On the other hand, if the power source is left OW
after the whole copying operation has been completed, the drum
. 1 and the skirt 17 and the blade 18 are adversely affec~ed in .
. their durability by continuous rotation of the drum 1. This
copying machine is, there~ore, so designed $hat in the event a
succeeding copying operation is not performed after the laps~
of a given amount of time upon completion of a copy.ing operation,
the drum 1 is automatically stopped to enter the suspension
condition even if the main switch 104 is in the ON position.
This period o~ time is set lonc3er than the time required for
drivinc~ outside the machine the transfer paper 21 last copied
and for clcaning the whole surface of the drum 1.
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l~Z67~8
The drum l is stopped in such a position that a
seam portion of the photosensi-tive layer (that is, a part
where`an ima~e does not appear) comes to the edge l8l of the
bla~e l8 to prevent the solidified toner from affec-ting the
im~ge. Furthermore prior to the stoppage of the drum l, all
the charges other than the AC charge are ae-energizea so that
the drum may be stopped with its entire surface which has
,
received an ~C charge discharging without any charge remaining
thereon. The reason for this is as follo~s: During use the
~rum l has its respective portions energized with aifferent
charges by charging thro~gh respective charger. As a result,
when entering the stoppage condition an~ at the same time
- . -
respective charges are de-energized, the respective portions
of the drum 1 are to be held in different conditions. The
` maintenance of such a charge condi~ion changes the `
;characteristic of the photosensitive layer~ For example, a
portion held in a negative charge by the negatiYe charger 15
having the greatest in~luence is not sufficiently charged
positively by the positive charger at the time of successive
copying, and only said portion is formed with an image having
a low concentration. This causes the life of the photosensitive
layer to be shortened. In order to avoia this, the present
copying machine is so designed th~t the drum l is stopped after
the whole surface of the drum has been uniformly discharged.
Furthermore, at the time of a stoppage condition, if
the copy button 107 (which serves also as a re-start button) is
depressed, the machine is restored to the condition prior to
the stoppage.
Electrical circuits will now be described~ The ;~
electrical circuit comprises an ~C lO0 V power source system
(Figure 3); a timer circuit (Figure ~), a control circuit
lFigure 5) for driving the original base for the book original~
a control circuit tFi~ure 6) for driviny the sheet original, a
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98
~ m detection circuit I and a circuit for d~ctincJ the
presenc~ oE sheets within the cassette (Figur~ 7), a jam
detection circuit II (Figure 8), a timing circuit (Figure 9)
-for paper feed and jam, a temperature control circuit (Figure
10), and an arran~ement (Fi~ure 11~ of rnicros~Jitches (on the
drum). ~igure 12 is a time chart for thc microswitches.
The copying machines shown in Figures 1 and 2 are
used ~7ith both sheet and book originals as descri~ed in the
foregoing by changing over a part of the machine, but the case
of the sheet original will first be described.
(1)' Power supply (Figure 1) ` ~ ,
'If the machine is in normal condition, when doo~ '
switches MSDl and,MSD2 and main switch SW (104) a numeral in
parentheses denotes a reference contained in the descrip~ion
of the machine,'(and the same applies hereinbelow) are turned
ON, power is supplied to the machine to place an AC 100 V circuit
and a DC 24V circuit i~ ~perative c~naition.
(2? AC circu,it ~Figure 3) and Timer circuit (Figure 4)
Then, at the same time when the main switch SW (104) is turned
ON, heaters Hl an~ H~ in the fixing part 46 are activatea to
heat the hot plate 28 ~MS6A and 6B are switches which activate
when a jam is detected and remain closea during normal
operation). A stir motor- (M~) for the developing machine 42
and cooling fans,FMl and FM2,are activated. A condenser C16
is'instantaneously charged through a resistor R41, a diode D15,,
and a resistor-R43 (the value of R41 ~ R43 is small) and at the
same time transistors Q17 and Q18 are forward biased through a
resistor R45 so that the transistors Q17 and Q18 are turned ON
and relay K6 is turned ON, contact K61 (Figure 3) of which
c~nnects the high voltage circuit of a stabilizer St2,to light
a ~luorescent lamp FL2.3~6).
(3) Timer circuit (Figure 4, delay of 12 seconds)
A condenser C13 is then charged through variable resistors VR6
,
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.
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~126798
- nd VR7 and a resistor R35 (however, ~he timc const~nt of the
timer circuit comprising VR6, VR7, R35 and C13 is controlled
by short-circuiting or opening the resis~or VR6 through a
thermost~itch SM2). More specifically, when the N channel gate
thyristor Q15 is turned ON after the lapse of the required
time (preparation of commencement), a charge o the condenser
C13 is applied through the resistor R30 to gates of SCR Q16 is
turned ON. ~t this time, the transistors.Q17 and Q18 are ON
in the condition described in paragraph ~2) above.so that
transistor Ql9 is OFF and forward biased by a pilot lamp PLl
of transistor Q20, resistors R49 and R50. The transistor Q20.
is then turned ON and.a relay K7 is turned ON to close its
contacts K71 and K72 (Figure 3) to activa-te main drive motor
Ml, thus rotating the drum 1. Simultaneously high voltage
transformer ~VT AC : DC is activated.
(4) Pre-idling (one rotation)
If.the machine is left unused for a long time, the photo-
sensitive body is restored from its fatigue, so~that it i~
necessary to uniformly expose the surface of the photosensitive
body to radiation prior to the prosecution of a copying
operation in order to place it in a usable fatigue condition~
As shown in Figure ll, the switching mechanism performs its
-timing function as given in the time chart in Figure 12 by
.
~eans of microswitches arranged on the drum 1. Even if a sheet
original is inserted simultaneously when the drum 1 begins to
rotate, a copying operation cannot be performed because the
grounded sides of microswitches MSlA and MSlB (Figure 6) are
disconnected by SCR.Q22 (Figure 4) so that the relay K~
. (Figure 6) cannot be turned ON. I~hen Microswitch MS3A (Figure
9) is activated, 'however, a signal is introduced into a ~ate
of transistor ~22 by the diode D22 and a resistor R56, and the
transistor Q20 is ON and the rel~y K7 is ON as mentioned above
so that a transistor Q21 is naturally turned ON by a resistor
, ~
-. . - 15 -
L26798
~3 bein~ self-e~ergized by the transistor ~21 and a resistor
5~, and there~ore the micro~witches MSl~ and ~SlB are grounded
through the diode D21, thus enab~ normal copying operations
to be performed from the second rotation of the drum.
_5? Cop~ing operation
Power is supplied to the ori~inal feed rollers 31 and 32 when
solenoid SL3 (Figure 6) is turned ON at the sheet original
(hereinafter calied an ori~inal) eed part 102, and ~hen an
original is inserted ~rom the original guide 37 the original is
transported le~twards as shown 'in Figure 2. Then, when the'
extreme end of the original reaches-the sheet origi~al timing
lamp Ll (5) light receiving element PD ~38~ (Figure 6), thoug'h
a transistor Q6 is forward biased by a variable resistor VR3
and a resistor R8 prior to its arrival, the light receiving
element PD (38) is directly'exposèd to the light of the lamp
Ll (5) so that ~he transistor Q6 is reversely biased by an
electromotive orce PD, turning the tran~istor Q7 ON.
- Mechanical operation is in ~art different between copying'of a
' sheet original and of a thick oriyinal ~book) as aescribed
previousl~, and therefore switching of the machine is'required.
In this case, a connector ON which performs the electrica~
switching is connected; also~ sheet originals are used so that'
the connector ON is connected and DC 24V is applied.
Simultaneously, when the remaining multipolar connectors ''
connect the lamp Ll and the light receiving element PD circu'its,
the transistor'Q6 is OFF, the transistor Q7 is ON, and a
transistor Q8 if OFF, a relay K4 not being operative. Then,
the voltages of t'he coil of the relay IC4 and a resistor R12
are produced with only impedance converted in the emitter of
a transistor ~9 SlD that voltage is applied to the gate of SCR
Q10 to turn a transistor Q10 ON and to turn a relay R8 ON by
resistors R13 and R14, and the power source of solenoids SL2 -'
and SL3 which control the original feed rollers is connected
- 16 -
~ 12~i798
the contact K82.
I~hen the extreme end o~ the original reaches the timing lamp
light receivinc~ element Ll (5).PD 38, ~lle light receivin~
element PD is not exposed to light radiation, so that the
electromotive orce o~ the light receiving element PD becomes
O, and the transistor Q6 is ON, the transistor Q7 is OFF, the
transistor Q8 and the relay ~4 are ON, the solenoid SL3 is
turned OFF by contact K41 of the K4 and.the solenoid SL2 is
turned ON by contact K52 and diode D9, and then the rollers 31
and 32 stop and the original also stops Then, when the drum 1
is rotated to the desired position, the microswitch MSlA is
turnea ON and the diode D21, the transistor Q22 in Figure 4
are connected ~rom the coil K41, the IC5 relay, contact K92,
diode D3, and the microswitch MSlA. When the relay K5 is turned
ON, the solenoid SL2 is turned OFF and the solenoid SL3 is
turned ON by the contact K52 to rotate the rollers 31 and 32'
.
- . - t~e original is transported leftwards in.synchronization with
the drum 1 and driven to the upper part of the machine by the
sheet origina~ second rollers 41 and 42 During that time,
~0 the original passes on the upper portion of the original glass
40 at the illumination part 39 and is exposed to.radiation
from the bo~tom by the two illumination lamps FL2 and FL3 (6~.
The.image is formed on the drum 1 at the exposure part 41 by
means of the reflection mirror 7 and the in-mirror lens 8. A
required electrostatic latent image. i5 $ormed by high voltage
. trans$ormers HVT AC and HVT DC and said optical system and
enters the developing machine 42. The latent image is then
developed by the developing solution stirred by the stir motor.
(6) P per feed tF'igure 9)
With respect to the transfer paper 21 stored in the cassette 20,
when the drum 1 is rotated and a microswitch MS2~ is activated,
a circuit comprising a contact K53, a diode D25, and the
: microswitch MS2A ~ON) is completed so that a solenoid 5L4 is
.
- 17 - . -
.......
- 1~2679B
~ tivated -to cause the norlnally rotating papcr feed rollers
22 to move downwards and thcn make contact with the upper-
most transfer paper, and one of the ~ransfer papers,
(hereinafter called "paper") is ~ransported,as described in
the operation of machine. ~lowever, the microswitch MS2A in a
circuit of the microswitch MS2~, the micros~itch MS13, rela~
KS3, and solenoid SL5'is turned OFF to s-top rotating timing
rollers 231 and 232 controlled by the solenoid SL5 so that
the paper stops at 2~1 and'232. When the,microswitch MS2A i5 `
turned OFF and at the same time the solenoid SL4 is turned OFF
: and the solenoid SL5 is turned ON, the paper is transported by
the timing rolle~s. The paper 21 transferred and separated in
a process as required is moved forward while being closeLy ' '
adhered to the hot plate 28 within the dr~ing-ana-fixing part
46 and driven onto the tray 32.
(7) Jam detection (Figures 8 and 9)
.
If paper is successively fed without the operator noticing
jamming of paper in its travel from the cassette to the tray
32, it will damage the separation belt 25 and other parts;
therefore it,is important that jamming of paper be detected.
The basic principle of the jam detection circuit is as follows:,
The relation between ts and tc is set so that ts C tc, where ,
ts is the time at which the paper feed switch MS2A or M,52B
~Figure 9) activa~es for a second time after its first
activàtion, and tc'is the time during which paper 21 moves the
distance opposite to the timing rol'Lers 231 and Z32~ the
separation roller 24, the hot plate 28, the ~irst ejection '
rollers 29i ana 29~, the lamp L4 of a detection device, and
, light receiving eLement CdS3 (Figure 4), and when said relation
is tS C tc, that ;s, when the paper 21 is jammed on the way,
the machine as a safety measure is caused to be stopped. As
sho~n in figure l:L, the drum on which the microswitches MSlB,
2B, and 3B (B group) are arranged in a symmetrical position
''
- 18 -
.
6798
' ,placed by 180 from a row of micros~itches MSlA, 2~, and
3~ (A group3, and microswitches MS4 and MS5 are ar.ranged in a
posi~ion displac~d by 90 therefro}n, is desi~ned so as to
copy, for its one rotation, one sheet .in the case of Size A3
paper and two sheets in case of Size A4 paper. Xn the case
of Size A4 paper, either the A ~roup of microswitches or the
B group may be empioyea for copying.
- When the original is inserted in the original 'feed rollers 31
and 32' the operation described above is performed to turn the
relay K4 ON and the microswitch MSlA is activated to turn the
relay K5 ON. When the microswitch MS2A is then turned ON and
the solenoid SL4 is ON, a transistor Q30 is turned ON by a
resistor R86 (Figure 8) and a transistor Q31 is turned OFF by
resistors R87t R88, and R89. At'this time, it is necessary to
judge which switch has been'activated, namely switches of t~e
A group or switches of the B group. Therefore, this "judgement"
is made by the switch MS2A of the A group and by the switch
MS~B of the B sroup,-and circuits corresponding to each group
in Figure 8 are used.
Since the microswitch MS2A is ON, a transistor Q35 (Figure 8~ is
forcibly turned ON by a resistor R96 so that the circuit of tha
B group is not activated. Since the transistor Q31 is OFF
(MS2B - OFF~, a condenser C25 is instantaneously chàrged by a
resistor R91 and a aiode D37, and a transistor Q32 is ~urned ON
- and a relay K10 is ON by a resistor 92, and even if the micro-
switch ~5S2A is tu:rned OFF, time being delayed by 0.5 second$ by
the condenser C25 and the resistor R92 so that the relay K10 is
in ON. Then, when the microswitch MS3~ (Figure 9) is turned ON t
a relay Kll is turned ON by contact NO of the relay K10, the
microswitch MS3A, and a diode D39, being self-maintained by-its
own contac~ Klll. Thereafter, the transistor Q32 is turned OFF
and the relay K10 is turned OFF. ~lternatively, if switches..of
the B group are used, the circuit of the B group functions in
-- 19 --
~L~Z6798
~luite the same way as the circuit of the ~ ~roup.
Paper s~arts to travel but does not r~ach the detection d~vice
comprising the lamp L~ and the photoconduc~ive elem~nt CdS3 as
shown in Figure 7, so that an amplification element Q25 is ON
and transistor Q26 is ON by resistors R74 and 75, and a timer
circuit comprising a resistor R77, a variable resistor VRll
and a condenser C20, an N channel qate ~hyristor Q27, a
thyristor Q28, and a resistor R82 has its condenser C20 short-
circuited to turn the thyristors Q27 and Q28 OFF. The
thyristor 29 is about to be turned ON with the arrival ofsignal to gate but will not be turned ON because contact K132
is closed and the microswitch MS2A is opened in connection wîth
the microswitch MS2A, diode D33 and contact K112. When the
microswitch MS2A is activated, that is, closed for the second
rotation followed by the first rotation, a circuit of the
microswitch MS2A, th~ diode D33, the contact K112, and the
solenoia SL7 is completed. Ho~ever, if paper (transported by
the action of the microswitch MS2A) reaches the detection device
as described-above, the transistor Q25 is turned OFF and the
transistor. Q29 is also turned OFF, and the solenoid SL7 is not
. operative. -.
When paper is ja~med on the way, the transistor Q25 is turned
ON and the transistor Q29 is turned ON, the solenoid SL7 i5
naturally turned ON to activate the microswitches MS6A and 6B
(Figure 3) actuated by the solenoid SL7, and the main drive
motor Ml, HVTAc, HVTDc, the heater Hl, and the heater H2 are
turned OFF. As a result, the machine is stopped and at the
same time a jam indicating lamp PL2 goes on. When the detec~ion
part is jammed to thereby intercept the light, the transistors
Q25 and.Q26 are OFF so that after the lapse of a given time the
condenser C20 is charged to turn the transistors Q27, Q28, and
Q39 ON, and the solenoid SL7 is actiYated to stop ~he machine
as described above.
. - 20 - ..
L267g8
~8) Means for substanti~lly ~ m~l~r~n~ the surf~ce potential
~ sensitive body durin~ the time from the automatic
stoppage (Figure 4) and the termillation of the copying process to
the stoppage of machine:
Since transistor Q16 stays ON in the preceding process, th~
capacitor C16 is not charged by the resistor R~l and the diode
D15. When the copying operation is effected, the capacitor C16
is always charged through diodes D:L6 and D17 (in the case of a
.. thick original) or through contact K42 (in the case of a sheet .
original), and the relay K6 is maintained in its operative
.-condition. In contradistinction, when a cop~ing operation is
not effected, the capacitor.C16 is not charged so that the
transistors Q17 and Q18 are turned OFF and the relay K6 is
turned OFF by the time constant determined by the capacitor 16,
variable resistor VR8, and the resistors R44 and R45; ~he
fluorescent lights FL2 and FL3 (6) are also turned OFF by the
contact K61 ~Figure 3). . -.
Further, the transistor Ql9 is turned ON, the lamp PLl goes on,
and the transistor Q20 is turned OFF, but, ~he relay K7 is
maintained in its operative condition by activation o the
contact K73 and of the microswitch MSlA (Figure 6).
Then, when.the microswitch MSlA is activated, the relay K7 is
turned OFF and HVTDC is turned OFF by the contact K72 (Figure
3), but the main drive motor Ml, the surface exposure lamp F~l,
and HVAC are maintained in their operative conditions by a
normally closed contact of the microswitch MS4 activated by
the drum itself. After about one rotation (300 to 330) followed
by activation of the microswitch MSlA (Figure 9), only the
~IVTAc (~C corona chargerj and the whole surface exposure lamp
FLl (12~ are activated during the time between the operation of
the microswitch MS4 and the stoppage of the main drive motor ~11.
to uniformalize the charge on the surface of the drum 1
(sensitive body) ana thereafter the rotation of the drum, is
. . - 21 -
.Z679B
-.topped. In this case, a similar result may be obtained by
performinq the exposure for only one rotati.On t~lrough only
the fluorescent lamp FLl, although its effect i5 inferior to
that of the AC corona charger.
9) Replenishment of paper (Figure 7)
~hen paper 21 is present ~et~Jeen the lamp L3 and the photo-
conauctive element cds2, the pho~ocon~uctive element cds2 is
: not exposed to light so that transistors Q23 and Q24 are OFF
and.relay K9 is also OFF, which represents the normal condition
and, the pilot lamp PL4 will not liyht. When paper is not
- present, the photoconductive element CdS2 is exposed to light -
. so that the transistors Q23 and Q24 are ON and the relay K9 is
ON and the pilot lamp PL4 is ON, and a copying start circuit
is aisconnecte~ by contact K91 of the relay K9 to initial:e
r.eplenishing of the paper. Fuxther, a microswitch MS15 is turned
OFP when the cassette 20 is properly set, thus representing
the set condit}on of the casse~te.
~1~) Temperàture control (Figure 10) . .
.
Variations-of resistor values due to the temperature of a
thermistor are aetected and the temperature of the hot plate is
controlled to a desired value.
Supposing that a control temperature is To and a thermistor
.(T~) is then Ro, when the temperature of the hot plate is at
To, the relation of variable.resistor VR12, to fixed resistors
R105, R106, and R107 in a bri~ge circuit is given by
(VR12 ( ~ ) -~ R105) x R107 = TH x R106, the potential
difference between inputs 2 and 3 of amplifier Q40 becomes 0,
the output terminal 6 is 0, the potential of the emitter of..
uni-junction transistor Q41 is 0, and an oscillation circuit
comprising a fixed resistor R110, the condenser C28, and a
transistor Q41 is not oscillate~ so as not to produce output in
a pulse transformer (TP), and accordingly a bi directional
thyristor Q42 is cut off and the main heater H2 (Figure 3)
,'
- - 22 -
Z679~51
.` .Inong heaters Tfll and Tl-12 is also turnecl OFF while only the
auxi].iary heater Hl is turned ON. However, the microswitch
MS6B is- in a closed position ~nd the temperature fuse FS is
properly connected.
~lso, ln the event -the temperature of the hot plate is in
excess of To, the output of transistor Q40 becomes 0 similarly
to the case as described above, the bi-directional thyristor
Q42 is OFF and the heate~ H2 also is OFF so that the hot plate
is not heated, and there~ore, the temperature stops rising~
Then, in the event the temperature of the hot plate becomes
lower than To, the value o~ the resistance of thermistor TH
becomes larger than Ro so that the input 2 of the ampli~ier Q40
will have a p~tential lower than the input 3, and the amp1ifier
Q40 normally perorms the ampli~ying operation. Accordingly,
the output of the amplifier Q40 is transmitted t~rough the
fixed resisto~ R110 and charges the capacitor C28, and when
the ch~rge.exceeds the ~otential set by the uni-junction
transistor Q41 itself, the charge of the condenser C28 is
rapidly discharged through the pulse transformer TP. The .-
?0 pulse current is appl.ied to the gate of transistor Q42 through
a diod2 D45 and a fixed resistor R112 to turn the transisto~
Q42 ON and also to turn the heater H2 ON and heat the hot plate.
.
When the temperature To is reached, the transistor Q42 and
the heater H2 are turned OFF as mentioned above, the same is
repeated therea~ter and a given temperature To is maintainea.
(11) Reciprocating movement of the ori~inal base (Figure 5~
Every part is normally operated in the manner described above
(in the case of the sheet original control circuit, the
connector ON in Figure 6 is excluded), and relay K8 is turned
30 OFF by the switching connector ON and contact K81 of the relay
K8 is turned ON (Fi~ure 5) to complete a relay Kl circuit.
When the copy button 107 (Figure 1) is depressed, the micro-
switch ~IS7 is turned ON and the relay Kl is turned ON, being
- 23 -
,
.- . ~
- ~;Z67~
self-maintained by its 0~7n contac-t Kll. Then, ~Jhen the rnicro-
s~itch.MSl~ on -the drum 1 is turned ON, the relay K2 is
energized and a clutch CLl is activated by a con-tact K22 to
- move the original base 2 leftwards in Figure 2 in synchroniz- .
ation ~Jith the peripheral speed of the drum 1, th~is performing
a slit exposure. .The solenoids SI.4 and SL5 are turned ON and
OFF on the way by means of a microswitch ~S14 (Figure 9)
mounted on the moving passage of the ori.ginal base 2 to feed
paper in synchronization with the original base 2. When the.
original base 2 reaches a position as required, microswitch
Mss is activated (Figure 5~ if Size A3 paper i5 used and .
microswitch MS10 is activated if Si~e A4 paper is used, ana a
relay K3 is turned ON and a relay K2 is turned OFF by cOntact
K32 of the relay K3 to activate a clutch CL~, and at the same
time the original base 2 is moved in a reverse direction and
when the base reaches a position as re~uired, microswitch MS8
is turned OFF, the relay K3 is turned QFF, and the clutch CL2
is turned OFF, th.en the base stops. Operations other than the
above are the same as in the case of the sheet original.
. Another embodiment will now be described, in which.an .
. optical system having an in-mirror lens, a reflection lens and
the like can be adjustea in order to solve.the problem of
une~enness ana fog in an image.
. One embodiment of a copying machine in which the
invention is applied will first be described, referring to
Figures 1 and 2.
Optical adjustments which generally take place are.
principally an adjustment of the magnification-between the
ori~inal and its image and an adjustment.of the focus. In the
case of an optical system using an in-mirror lens as in the
copying machine of the preferred embodiment, the former is ~one
by adjusting the ratio of the light path length from the ..
original surface to the lens, to the light path len~th from the
. - 24 -
LZ~9~3
lens to the exposure surface; the latter is done b~ adjusting
t~ light path length by moving the in-mirror lens back ~nd
forth on its optical axis
Although a case of copying with equal magnification
will be described, in the following explanation a case of some
other magnifications is described for convenience.
In an optical syste~ having a reflection mirror 7
and an in-mirror lens 8 as shown in this embodiment, the
- a~justment of magnification, that is, the work for equalizing
light path lengths back and forth of a lens for light used in
copying is made in several ways. A first method'is to vert- ;
ically move the original surface so as to make it equal to
t~e distance from the in-mirror lens 8 to the exposure surface
41. This method is carried out; for example, by inserting a
spacer under the gl~ss 55 of the original surface and the
construction for practicing the method is simple; the method
however is not suitable for mass production because'it is
troublesome in fine adjustment and in a~it;on grea~ care is
required in handling breakab~e glass. A second method, is to
adjust the light path length from the original to the lens by
adjusting the reflection mirror 7. Accoraing to this method,
' it is easy to have a construction in which fine adjustments
can be-madei this method, however, is another one which is no~
- suitable for mass production because the aajusting work should
be done inside the machine, and in addit'ion a slight
inclination o~ the mirror greatly affects the image so'that
considerable skill and time may be required for a complete
adjustment.
Accoraing to the preferred embodiment, the adjustment
.
of magnification is carried out by rotating a case 57, which is
provided with'an in-mirror 8 and a reflection mirror 7 as sho~n 5
in Figure 13, on the shaft 58. This principle is ~cscribed with
re~erence to Figures 1~ and 15. Yigure'l~ illustrates a
.
- 25 -
. ,.
:~Z6798
sliglltly modifi~d optical sys~em, in ~Ihich ~n optical axis of
the in-mirror lens 8 is m~d~ ho~i~ontally p~rallel with the
original surfacc, it is widely used in the copying machine.
Not. much difference exists between the conventional optical
system and the optical sys-tem illustrat~d in Figure 1~, with
the exception of their arran~emen~s. Therefore, the
description referring to Figure 15 will be made in accordance
with the embodiment of the optical system shown in Figure 14.
- In Figure 15, there are shown an original surface D
and an exposure surface Er and an exposure part B is determined.`
Reference M denotes a reflection mirror and L is a main plane
for the in-mirror lens. It is assumed that the optical system
is assembled as shown by the two-dot line. In this case, an
image on the exposure part B is identical with t~e image of the
original positioned at a. As a result, the magnification Qf the
image is given by ( B L' ) / ( a R2' ~ R'2L' ), which is
a ratio between the ~ight path ~engt~s at bacX and forth of
lens. In general, the value of this ratio is not 1 with the
accumulation of various errors. In Figure 15, there is shown
a point A', at which an image of equal magniflcation is
obtained, that is, at which ( A'R2' ~ R'2L' ) = ( L'B ~ is
obtained. If the mirror M and the in-mirror lens-L are rotated
at a suitable angle ~ e on the point O from the a~oresaia state~
a point _ is obtained, in which a and A' are in line as
indicated by the one dot line in Figure 15. More specifically,
the image of the original at A is formed in B and its
.
magnification is t AR2 ~ ~2L ) = LB, which corresponds to 1,
completing the adjustment of magnification
This method of adjustment has such advantages that
.
adjustment can be done by a simple and accurate operation,
requiring no skill by an operator, and furthermore such an
op~ration may be done in a short time.
Alsof it is preferable to select a position of a
- 26 -
. .
. .: ,. . . .
~2679~
center O of rotation to be placed where the li~ht path length
BL does not vary much, i.e., the light pa~h, the optical axis
of the lens, or a place in the vicinity of e~tension thereof,
in the sense of having a slight influence on the adjustment of
focus to take place in succession t;o said ad~ustment of
magnifica~ion, or ~o select places apart ~rom the refl~ction
mirror M in order to xeduce varia~:ion aA of the position A o~
the original.
Figures 1 and 2 illustrate a copying machine in which
a method for adjusting the optical system according to the
invention is applied.
This copying machine is of the liquid deve3opmen~
transfer type, the structure of which is designea principally
for sheet-like originals such as documents and also is
designed to easily ma~e copies of thick originals such as books
or the like.
Stil~ another embodiment ~iill now be described, which
embodiment has as its object to provide an even image over the
whole slit by adjusting the exposure in the optical system in
order to solve the problem of unevenness o~ the image.
A transfe~ type electrophotographic copying machine
- as shown in Figure 1 is of the type in which an original O is
transported by means of feed rollers 31~ 3~ 41~ and 42~ and
the oxiginal O is exposed to light radiation rom the bottom of
an original glass 40 by two illumination lamps 6 and 6, and the
light reflected therefrom is received by a mirror 7 and an in-
mirror lens 8 to form an original image on the photosensitive
drum 1, and at that time the quantity of light at the exposure
part 41 is to be determined by a slit 112 of a slit plate 11~
(shown in Figure 16) arranged in the vicinity of the exposure
part~
In such an exposure system, however, fluorescent
lamps, halogen 3amps or the like are generally used as the
.' ' . ' ' :
- 27 -
: L:lZ~798
- illun~in~ion l~mps 6 and 6 so ~hat hoth ~nds of the lamp are
weaker in brightness than the central portion and both side
portions of the original are exposed to light ~eaker than the
central portion. Furthermore, the quantity of light in the
pcriphery thereo is less than -tha~ in the central por-tion
due to the nature of the lens. Rs a result, there is projected
an image on thè drum 1~ which corresponds to both end portions
of the slit 112, darker than that corresponding to the central
portion of the slit 112 under these influences, so that thereby
it is impossible to obtain an entirely unifQrm image.
. This invention has as one of its objects to eliminate
,
the problems noted above-, wherein a control plate 124 is
mounted on the slit plate 111, the control plate 124 being
reciprocated.in the width direction of the slit 112, said
reciprocation causing a vari~tion in the ratio of width between
the central portion of the slit 112 and both side portions.
In a case as shown, the control plate 124 comprises
two short plates 113 and 113 of the same shape as shown in
Figures 17 and 18. The length of the short plate 113 is about
on~ half of the-to~al length of the slit 112, and about one . :.
third (1/3) of the side 114 opposite the slit 112 is made a
straight line approximately parallel with the long side 115 of
the slit 112, and approximately the remaining two thirds (2/33
thereof is gr~dually tapered towards the outside at an angle . . -
.. of inclination 4. In order to form a control plate 124 .according to the invention, the two short plates 113 and 113 .
are oppositely loc:ated with linear portions a and a slightly
overlapped and.retractably mounted on the slit plate 111 with
respect to the wiclth direction of the slit by means of screws .
116 and 117, and ~;lots 118 and 119~ In a case as shown, the
slit plate 111 is detachably fitted between guides 120 and 121
provided on the support frame 125 of a charger 10. The
r~ference character 123 denotes a window pervious to iigh~ made
.
. - 28 -
.. . .
Z~7g8
;
in the support frame 125. The ratio of the lin~ar portion a
of the control plate 12~ to the inclined portion b is a value
obtained by exp~riment of the ~ngle of inclination Q. Further-
more, the control plate 124 may also comprise one long plate.
Since the invention has the construction described
above, in the event the both ends of the illumina~ion lamps 6
and 6 are turned black to reduce its brightness as compared
ith the central por~ion, the exposure over the whole area o~ .
the slit 112 can be uniformalizea by untightening the mounting
screws 116 and 117 on the control plate 124 to move forward -
the control plate 124 so that the ratio of the width of the
central portion in the slit 112 to that of both side portions
may be variea.
~urthermore, novel improvements in ~he electro-
photographic device according to the invention will be
introduced in the following:
This improvement relates.to a paper rejection tray.
- for the copying machine, and has as its object to proviae a
paper rejection tray which can respond to copying paper such
as transfer paper and photosensi~ive paper and the like of
various sizes_ . -
One embodiment of a copying machine in which thi~ .
invention is applied will be described. The paper rejection
tray may be divided broadly into two types. One has a down-
waraly inclined plane from a paper rejection port, while the
other has an upwardly inclined plane from the paper re~ection
port. . ~.
It is possible for the former falling type tray to
.easily accumulate copying paper as long as there is some head,
but where the paper rejection port is positioned at the lower
part of the machine body, or where the cassette is arranged at
the lower part of the paper rejection port as shown in the
copying machine of the foregoin~ embodiment so that.a suff.icient
.
,~
hcad may not be provi~ed, the copyin~ paper cannot be
coMpletely dropped and the rcar end o~ the paper is caught i.n
the paper rejection port thus to cause succeedincJ copying
paper to be jammed. As for the lat~er rising type tray,. there
is no need of apprehension about a head as in the falling type,
but when copying paper of large si~e is weak in fi.rmness,
thus increasing the friction resistance between the paper and
the inclined plane of the tray, the extreme end of the copying
paper tends to cease moving on the way of the tray to cause
succeeding copying paper to be jammed as in the aforesaid
falling type tray. Both types have such disadvantages that a
tray occupies a good deal of space for the copying paper which
is largest in.size and gets in the way when the cassette is
replaced, which are not favorable in function and in operation.
This invention has as one of its objects to eliminate
th~ aforesaid disadvantages, and pravides a paper rejection
- tray comprising a main tray 32 having an upwardly inclined ..-
plane with respect to the moving direction of the copying.paper to be rejected and an auxiLiary tray 321 having a.do~n-
~ard inclined plane.arranged at the ex~remè end thereo~.
Therefore, in the case where copying paper Pl of
small size is used, the copying paper Pl sent out of the pape~
re~ection port 54 moves on the upwardly inclined plane of thé
main tray 32, and when the rear end of the paper comes out ofthe paper xejection port ~4, it is accumulated on the main tray
32. In this case, as long as the copying paper Pl has a
firmness similar to that of conventional paper, it never bends.
When a copying paper P2 of large size is used, the extreme end
of the copying paper P2 is bent downwardly by its own weight
~rom the upper end of the inclined plane of the main tray 32,
moves downwardly along the inclined plane of the auxiliary
tray 321, and accumulated in the form of mountain-shape on the
main tray 32 and the aux.iliary tray 321.. In this case, it is
~ 30
1~;26~9~3
prcferable to ~Ise a covcr Cl for ol~ening and c].osing the
cassette C as a part of the tray ~nd to use the handle C2
thereof as a stopper of the copying paper P2.
I~ith the construction described above, even if a
head cannot be provided so largely, for the cassette is
positioned at the lower part of the paper rejection port,
copying paper of small size as well as of large size can
accurately be accumulated by prope:rly combining the upwardly
inclined plane and. the downwardly inclined plane, and.the
cassette can easily be removed. Furthermore, it is possible
to use the cassette cover as a part of the tray and it is
possibl~ to provide a compact construction by encasing a tray
- within the length of cassette as shown in Figure 19.
. Furthermore,.the main tray 32 and the.auxiliary tray
321 may be formed inte~rally, but as shown in Figure 20 both
trays 32 and 321 can be so constructed as to be opened or
. closed with a hinge so that when the auxiliary tray 321 is
used for copying paper of small size, it may be lapped ovex the
main tray 32, and when the ~ray 321 i5 used for copying paper
of large size, it may be left open for use, thus providing a
tray which functions effectively.
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' ' ; ' '.,
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- 31 ~
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